Topic: Bassoon French Whisper Key?

Will those of you familiar with the French Whisper key (on the German bassoon), please delineate how you've found it useful? When and where, both technically and in repertoire would be useful. Oh,, this is where there is only the FWK installed separately from other auxiliary modifications. Thanks for your time.

Nicholas Evans-Bassoonist, Bassoon Repair and Restoration Mechanic.